Jetting

[dirtking]

I installed a 48 pilot jet/2 turns fuel screw out on my 2006 YZ450F today and when i rev about 1/4 throttle it misses and it still backfires on deceleration although not as bad as with stock pilot jet. Everything else on the bike is stock. Any help would be appreciated!

[Eddie Sisneros]

while riding it?

[dirtking]

It doesnt miss while riding it but when i am practicing starts and have it revved it misses. It backfires when it gets into low revs on deceleration.

[Eddie Sisneros]

concentrate on what hapens with a load on the motor.

[dirtking]

Eddie,

I ran the test for the pilot circuit and the bike will run with the fuel screw all the way in. It has the 48 pilot jet and rest stock. While riding it, it still backfires when i let off the throttle. Also when i go into a corner and it is at low rpms if i crack the throttle on real fast it cuts out then picks up and then starts reving normally? Any help would be appreciated thanks!

[dirtking]

Do i need do drop the pilot to a 45 or leave the 48? Would changing the needle position help any? Any help would be helpful

thanks

chance

[Eddie Sisneros]

go to a 45 pilot jet.

is the rest of the jetting stock?

[dirtking]

Yes the rest of the jetting is stock. just try the 45 and see what happens? Would i need to change the clip postion on the needle?

[Eddie Sisneros]

not at this time.one change at a time.

[dirtking]

I put the 45 pilot in and adjusted the fuel screw how you described and it is 2 turns out. Still pops on deceleration. Any ideas?

Thanks

[Eddie Sisneros]

like a machine gun?big explosions?just a few pops?

[dirtking]

Mostly littles pops when it gets into the low revs and occasionaly a couple big pops.

[Eddie Sisneros]

sounds pretty normal to me.

trying to tune the decel pop completely out most always results in soggy performance on the throttle.

[dirtking]

The only other thing is that when i go into a corner and it is just kinda idleing along and then i open the throttle real fast it will cut out for a second then pickup and then go like a banshee. Other than that it runs like a raped ape. Thanks for all your help!

[Eddie Sisneros]

better or worse when hot?

[dirtking]

It gets alil bit better when it is hot but not alot

[Eddie Sisneros]

try raising the needle 1 clip.

[dirtking]

So that will make it richer on the needle correct? I will have to take the carb completely off to do this or will i be able to take the tank off and get it from there? Thanks

[Eddie Sisneros]

yes richer.you can do it with the carb in place.